High heat flux two-phase cooling in silicon multimicrochannels

Abstract

This paper presents performances of two-phase cooling of a chip at very high heat flux with refrigerant R236fa in a silicon multimicrochannel heat sink. This heat sink was composed of 134 parallel channels, 67 μm wide, 680 μm high, and 20 mm long, with 92-μm-thick fins separating the channels. The base heat flux was varied from 3 to 255 W/ cm2, the volume flow rate from 0.18 to 0.67 l/min, and the exit vapor quality from 0 to 80%. The working pressure and saturation temperature were set at 273 kPa and 25 °C, respectively. The present database includes 1040 local heat transfer coefficients. The base temperature of the chip could be maintained below 52 °C while dissipating 255 W/cm2 with 10 ∼ °C of inlet subcooling and 90 kPa of pressure drop. A comparison of the respective performances with an extrapolation of the present results shows that two-phase cooling should be able to cool the chip 13 K lower than liquid cooling for the same pumping power at a base heat flux of 350 W/cm2. © 2008 IEEE.